Atlas Copco GA 37 VSD - Page 101

Instruction book
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1904 0504 83 ϵϵ
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4.
' (
ï

 H  ò î   ò *  ó   

  ï ñ A



B
The Ryznar Stability Index is a parameter for predicting whether water will tend to dissolve or
precipitate calcium carbonate. The adhesion of scaling depositions and their effect are different on
different materials, but the equilibrium of the water (scaling or corrosive) is only determined by its
actual pH value and by the saturation pH value (pH
s
). The saturation pH value is determined by the
relationship between the calcium hardness, the total alkalinity, the total solids concentration and the
temperature.
The Ryznar Stability Index is calculated as follows:
RSI = 2*pH
s
-
pH, in which
• pH = measured pH (at room temp) of the water sample
• pH
s
= pH at saturation
pH
s
is calculated from:
pH
s
= (9.3 + A + B) - (C +
D), in which
• A : depends on the total solids concentration
• B : depends on the water temperature at the outlet of the heat exchanger
• C : depends on the calcium hardness (CaCO
3
)
• D : depends on the HCO
3
-
concentration or M-alkalinity
The values of A, B, C and D can be found in below table:
á
ß Ù 6 2 I
á
Þ 4 â Þ Ü 6 Ù à Ü Þ J
C
6 Ú 6 Ü Û ç Þ 3 3
C
5 K I 2 L 6 2 Ø ç Ø Ù Ý M
Û Ø 3 3 ß 2 9 Þ Û D N
C G O P P Q R S R T
U
V O P P Q R S R T
U
V
3 ß 2 Ø Û 3
D 4 è W 2
G
< 30 0.1 0 - 1 2.3 9 - 11 0.6 10 - 11 1.0
30 - 320 0.2 2 - 6 2.2 12 - 14 0.7 12 - 14 1.1
> 320 0.3 7 - 11 2.1 15 - 17 0.8 15 - 17 1.2
12 - 16 2.0 18 - 22 0.9 18 - 22 1.3
17 - 22 1.9 23 - 28 1.0 23 - 28 1.4
23 - 27 1.8 29 - 35 1.1 29 - 35 1.5
28 - 32 1.7 36 - 44 1.2 36 - 44 1.6
33 - 38 1.6 45 - 56 1.3 45 - 56 1.7
39 - 43 1.5 57 - 70 1.4 57 - 70 1.8
44 - 49 1.4 71 - 89 1.5 71 - 89 1.9
50 - 55 1.3 90 - 112 1.6 90 - 112 2.0
56 - 61 1.2 113 - 141 1.7 113 - 141 2.1
62 - 67 1.1 142 - 177 1.8 142 - 177 2.2
68 - 73 1.0 178 - 223 1.9 178 - 223 2.3
74 - 79 0.9 224 - 281 2.0 224 - 281 2.4
80 - 85 0.8 282 - 355 2.1 282 - 355 2.5
86 - 91 0.7 356 - 446 2.2 356 - 446 2.6
92 - 95 0.6 447 - 563 2.3 447 - 563 2.7
564 - 707 2.4 564 - 707 2.8
708 - 892 2.5 708 - 892 2.9
893 - 1000 2.6 893 - 1000 3.0